1 /* libunwind - a platform-independent unwind library
2 Copyright (C) 2003-2004 Hewlett-Packard Co
3 Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
4
5 Permission is hereby granted, free of charge, to any person obtaining
6 a copy of this software and associated documentation files (the
7 "Software"), to deal in the Software without restriction, including
8 without limitation the rights to use, copy, modify, merge, publish,
9 distribute, sublicense, and/or sell copies of the Software, and to
10 permit persons to whom the Software is furnished to do so, subject to
11 the following conditions:
12
13 The above copyright notice and this permission notice shall be
14 included in all copies or substantial portions of the Software.
15
16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
23
24 #include <string.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <unistd.h>
28
29 #include <libunwind.h>
30 #include "compiler.h"
31
32 #include <sys/resource.h>
33 #include <sys/time.h>
34
35 #define panic(args...) \
36 do { fprintf (stderr, args); exit (-1); } while (0)
37
38 long dummy;
39
40 static long iterations = 10000;
41 static int maxlevel = 100;
42
43 #define KB 1024
44 #define MB (1024*1024)
45
46 static char big[64*MB]; /* should be >> max. cache size */
47
48 static inline double
gettime(void)49 gettime (void)
50 {
51 struct timeval tv;
52
53 gettimeofday (&tv, NULL);
54 return tv.tv_sec + 1e-6*tv.tv_usec;
55 }
56
57 static int NOINLINE
measure_unwind(int maxlevel,double * step)58 measure_unwind (int maxlevel, double *step)
59 {
60 double stop, start;
61 int level = 0;
62 void *buffer[128];
63
64 start = gettime ();
65 level = unw_backtrace(buffer, 128);
66 stop = gettime ();
67
68 if (level <= maxlevel)
69 panic ("Unwound only %d levels, expected at least %d levels\n",
70 level, maxlevel);
71
72 *step = (stop - start) / (double) level;
73 return 0;
74 }
75
76 static int f1 (int, int, double *);
77
78 static int NOINLINE
g1(int level,int maxlevel,double * step)79 g1 (int level, int maxlevel, double *step)
80 {
81 if (level == maxlevel)
82 return measure_unwind (maxlevel, step);
83 else
84 /* defeat last-call/sibcall optimization */
85 return f1 (level + 1, maxlevel, step) + level;
86 }
87
88 static int NOINLINE
f1(int level,int maxlevel,double * step)89 f1 (int level, int maxlevel, double *step)
90 {
91 if (level == maxlevel)
92 return measure_unwind (maxlevel, step);
93 else
94 /* defeat last-call/sibcall optimization */
95 return g1 (level + 1, maxlevel, step) + level;
96 }
97
98 static void
doit(const char * label)99 doit (const char *label)
100 {
101 double step, min_step, first_step, sum_step;
102 int i;
103
104 sum_step = first_step = 0.0;
105 min_step = 1e99;
106 for (i = 0; i < iterations; ++i)
107 {
108 f1 (0, maxlevel, &step);
109
110 sum_step += step;
111
112 if (step < min_step)
113 min_step = step;
114
115 if (i == 0)
116 first_step = step;
117 }
118 printf ("%s: unw_step : 1st=%9.3f min=%9.3f avg=%9.3f nsec\n", label,
119 1e9*first_step, 1e9*min_step, 1e9*sum_step/iterations);
120 }
121
122 static long
sum(void * buf,size_t size)123 sum (void *buf, size_t size)
124 {
125 long s = 0;
126 char *cp = buf;
127 size_t i;
128
129 for (i = 0; i < size; i += 8)
130 s += cp[i];
131 return s;
132 }
133
134 static void
measure_init(void)135 measure_init (void)
136 {
137 # define N 100
138 # define M 10 /* must be at least 2 to get steady-state */
139 double stop, start, get_cold, get_warm, init_cold, init_warm, delta;
140 struct
141 {
142 unw_cursor_t c;
143 char padding[1024]; /* should be > 2 * max. cacheline size */
144 }
145 cursor[N];
146 struct
147 {
148 unw_context_t uc;
149 char padding[1024]; /* should be > 2 * max. cacheline size */
150 }
151 uc[N];
152 int i, j;
153
154 /* Run each test M times and take the minimum to filter out noise
155 such dynamic linker resolving overhead, context-switches,
156 page-in, cache, and TLB effects. */
157
158 get_cold = 1e99;
159 for (j = 0; j < M; ++j)
160 {
161 dummy += sum (big, sizeof (big)); /* flush the cache */
162 for (i = 0; i < N; ++i)
163 uc[i].padding[511] = i; /* warm up the TLB */
164 start = gettime ();
165 for (i = 0; i < N; ++i)
166 unw_getcontext (&uc[i].uc);
167 stop = gettime ();
168 delta = (stop - start) / N;
169 if (delta < get_cold)
170 get_cold = delta;
171 }
172
173 init_cold = 1e99;
174 for (j = 0; j < M; ++j)
175 {
176 dummy += sum (big, sizeof (big)); /* flush cache */
177 for (i = 0; i < N; ++i)
178 uc[i].padding[511] = i; /* warm up the TLB */
179 start = gettime ();
180 for (i = 0; i < N; ++i)
181 unw_init_local (&cursor[i].c, &uc[i].uc);
182 stop = gettime ();
183 delta = (stop - start) / N;
184 if (delta < init_cold)
185 init_cold = delta;
186 }
187
188 get_warm = 1e99;
189 for (j = 0; j < M; ++j)
190 {
191 start = gettime ();
192 for (i = 0; i < N; ++i)
193 unw_getcontext (&uc[0].uc);
194 stop = gettime ();
195 delta = (stop - start) / N;
196 if (delta < get_warm)
197 get_warm = delta;
198 }
199
200 init_warm = 1e99;
201 for (j = 0; j < M; ++j)
202 {
203 start = gettime ();
204 for (i = 0; i < N; ++i)
205 unw_init_local (&cursor[0].c, &uc[0].uc);
206 stop = gettime ();
207 delta = (stop - start) / N;
208 if (delta < init_warm)
209 init_warm = delta;
210 }
211
212 printf ("unw_getcontext : cold avg=%9.3f nsec, warm avg=%9.3f nsec\n",
213 1e9 * get_cold, 1e9 * get_warm);
214 printf ("unw_init_local : cold avg=%9.3f nsec, warm avg=%9.3f nsec\n",
215 1e9 * init_cold, 1e9 * init_warm);
216 }
217
218 int
main(int argc,char ** argv)219 main (int argc, char **argv)
220 {
221 struct rlimit rlim;
222
223 rlim.rlim_cur = RLIM_INFINITY;
224 rlim.rlim_max = RLIM_INFINITY;
225 setrlimit (RLIMIT_STACK, &rlim);
226
227 memset (big, 0xaa, sizeof (big));
228
229 if (argc > 1)
230 {
231 maxlevel = atol (argv[1]);
232 if (argc > 2)
233 iterations = atol (argv[2]);
234 }
235
236 measure_init ();
237
238 unw_set_caching_policy (unw_local_addr_space, UNW_CACHE_NONE);
239 doit ("no cache ");
240
241 unw_set_caching_policy (unw_local_addr_space, UNW_CACHE_GLOBAL);
242 doit ("global cache ");
243
244 unw_set_caching_policy (unw_local_addr_space, UNW_CACHE_PER_THREAD);
245 doit ("per-thread cache");
246
247 return 0;
248 }
249